1. Field of the Invention
The present invention relates to a method of manufacturing a multilayer wiring board including a plurality of insulating layers, each of which includes a ceramic layer and a shrinkage suppression layer that is stacked on top of the ceramic layer, being fixed to one another by applying pressure and then fired, a probe card that includes a multilayer wiring board that is manufactured by the method, and a multilayer wiring board.
2. Description of the Related Art
In the related art, a multilayer wiring board is capable of having high dimensional accuracy such as a multilayer wiring board 100 illustrated in FIG. 13. The multilayer wiring board 100 includes a multilayer body including a plurality of insulating layers 101, each of which includes a ceramic layer 101a and a shrinkage suppression layer 101b that is stacked on top of the ceramic layer 101a, being stacked on top of one another in a predetermined order, fixed to one another by applying pressure, and then fired, and various wiring electrodes 102 and via conductors 103 are formed on major surfaces of the insulating layers 101 and in areas inside the insulating layers 101. In this case, the shrinkage suppression layers 101b suppress shrinkage of the ceramic layers 101a at the time of firing of the multilayer body, and thus, high dimensional accuracy can be obtained for the multilayer wiring board 100, which is a completed body, after the firing. An example of the related art is International Publication No. WO 2008/108172 (for example, see [0028] to [0031], and FIG. 3).
However, in the multilayer wiring board 100 of the related art, the wiring electrodes 102 are patterned on the shrinkage suppression layers 101b of the insulating layers 101, and thus, when the insulating layers 101 are stacked on top of one another, in the same shrinkage suppression layer 101b, there will be a portion that is interposed between the corresponding ceramic layer 101a and one of the wiring electrodes 102 and a portion that is not interposed between the corresponding ceramic layer 101a and one of the wiring electrodes 102. In this case, when the layers of the multilayer body are fixed to one another by applying pressure, in the same shrinkage suppression layer 101b, a compressive stress that is applied to a portion that is interposed between the corresponding ceramic layer 101a and one of the wiring electrodes 102, is larger than a compressive stress that is applied to a portion that is not interposed between the corresponding ceramic layer 101a and one of the wiring electrodes 102, and the thickness of the portion of the shrinkage suppression layer 101b, which is interposed between the corresponding ceramic layer 101a and one of the wiring electrodes 102, is smaller than the thickness of the portion of the shrinkage suppression layer 101b, which is not interposed between the corresponding ceramic layer 101a and one of the wiring electrodes 102. In this case, particularly the thickness of a portion of the shrinkage suppression layer 101b around the periphery of one of the wiring electrodes 102 becomes small. In this case, a shrinkage suppression force of a portion of the shrinkage suppression layer 101b the thickness of which has been reduced acting on the corresponding ceramic layer 101a decreases, and in the multilayer wiring board 100, there will be portions of the ceramic layers 101a that have different amounts of shrinkage at the time of firing. In addition, in the case where the shrinkage suppression force decreases as described above, the degree of shrinkage of the ceramic layers 101a in a planar direction increases, and the degree of shrinkage of the ceramic layers 101a in a vertical direction decreases. Thus, for example, portions of the surface of the multilayer wiring board 100 around the periphery of the corresponding wiring electrodes 102 protrude, and the flatness of the multilayer wiring board 100 may deteriorate, and warpage, a fracture, a crack, and the like may occur in the multilayer wiring board 100. In addition, in the case where this type of multilayer wiring board such as the multilayer wiring board 100 is used in a probe card or for rewiring, there will be a portion in which the wiring electrodes 102 are concentrated in a portion of the multilayer wiring board 100, and thus, the above-described problems will become notable.